In general, a suspension is a device that prevents vibration or shock which a vehicle shaft receives from a road surface from being directly transferred to a vehicle body to prevent the vehicle body or freight from being damaged and improve ride comfort when a vehicle is driven by connecting the vehicle shaft and a vehicle body.
In particular, an air suspension system includes an air spring, an air tank, an air supply unit (an air compressor and a solenoid valve), and a controller and sensors controlling the same.
The air suspension system is configured in such a manner that when a load decreases and a vehicle height thus increases, the solenoid valve (leveling valve) operates, and as a result, air in the air spring is discharged and when the load increases and the vehicle height thus decreases, the air is replenished in the tank to constantly maintain the vehicle height. Therefore, when the load increases, the spring becomes hard and when the load decreases, the spring becomes soft.
As described above, the air suspension system provides an automatic leveling function in order to maintain a predetermined vehicle height in modes by providing various modes.
Meanwhile, when an error occurs in the tire or the air spring of the vehicle, a jack is inserted between the road surface and a narrow space of the vehicle body to raise the vehicle body at a predetermined height for replacement or repairing.
The replacing and repairing operations become operations which are difficult and hard for a driver.
In order to solve such a problem, development of a system that can facilitate the replacing or repairing operation is required by controlling the height of the vehicle body by using the air suspension.